In recent years, there have been proposed and developed various vehicle dynamics control technologies or various vehicle-behavior control technologies suitable for automotive vehicles employing a differential limiting control system, capable of limiting differential actions of respective differential units, such as a center differential, and front and rear differentials. One such vehicle dynamics control apparatus has been disclosed in Japanese Patent Provisional Publication No. 2000-344077 (hereinafter is referred to as “JP2000-344077”), corresponding to European Patent Application No. 00 112 237.3 whose date of filing is Jun. 7, 2000. As is generally known, there is a difference between a change in dynamic vehicle behavior in a locked state of a center differential and a change in dynamic vehicle behavior in a free state of the center differential. In due consideration of such a difference of the dynamic-vehicle-behavior change between the differential lock state and the differential free state, the vehicle-behavior control apparatus disclosed in JP2000-344077 operates to reduce engine power output and additionally to inhibit braking force control for each individual road wheel in the center-differential locked state. Thus, instead of using vehicle behavior control suitable for a two-wheel-drive (2WD) mode, vehicle behavior control peculiar to a four-wheel-drive (4WD) mode has to be used. Generally, there are the following three ways to control dynamic vehicle behavior during the 4WD mode in which the center differential is locked.
{circle around (1)} The first way is to change (or to reduce) the magnitude of a braking force applied to each road wheel, during vehicle dynamics control in the center-differential lock mode (or in the 4WD mode).
{circle around (2)} The second way is to inhibit braking force control for each individual road wheel, during vehicle dynamics control in the center-differential lock mode (or in the 4WD mode)
{circle around (3)} The third way is to reduce engine power output under a condition that braking force control is inhibited, during vehicle dynamics control in the center-differential lock mode (or in the 4WD mode).